U.S. patent application number 16/889858 was filed with the patent office on 2021-12-02 for locking backpressure valve.
This patent application is currently assigned to Baker Hughes Oilfield Operations LLC. The applicant listed for this patent is Larry Thomas Palmer, Erik Van Steveninck, Steve Wilson, III. Invention is credited to Larry Thomas Palmer, Erik Van Steveninck, Steve Wilson, III.
Application Number | 20210372229 16/889858 |
Document ID | / |
Family ID | 1000004886209 |
Filed Date | 2021-12-02 |
United States Patent
Application |
20210372229 |
Kind Code |
A1 |
Palmer; Larry Thomas ; et
al. |
December 2, 2021 |
LOCKING BACKPRESSURE VALVE
Abstract
A downhole tool includes a tubular having an outer surface and
an inner surface defining a flowbore having a longitudinal axis,
and a backpressure valve cartridge arranged in the flowbore. The
backpressure valve cartridge includes a valve seat and a flapper
valve pivotally mounted relative to the valve seat. The
backpressure valve cartridge is shiftable along the longitudinal
axis to shift the flapper valve between a first position, wherein
the flapper valve rests on the valve seat, and a second position,
wherein the flapper valve is pivoted away from the valve seat.
Inventors: |
Palmer; Larry Thomas;
(Spring, TX) ; Van Steveninck; Erik; (Houston,
TX) ; Wilson, III; Steve; (Magnolia, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Palmer; Larry Thomas
Van Steveninck; Erik
Wilson, III; Steve |
Spring
Houston
Magnolia |
TX
TX
TX |
US
US
US |
|
|
Assignee: |
Baker Hughes Oilfield Operations
LLC
Houston
TX
|
Family ID: |
1000004886209 |
Appl. No.: |
16/889858 |
Filed: |
June 2, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 34/14 20130101;
E21B 2200/05 20200501 |
International
Class: |
E21B 34/14 20060101
E21B034/14 |
Claims
1. A downhole tool comprising: a tubular having an outer surface
and an inner surface defining a flowbore having a longitudinal
axis; a backpressure valve cartridge arranged in the flowbore, the
backpressure valve cartridge including a valve seat and a flapper
valve pivotally mounted relative to the valve seat, wherein the
backpressure valve cartridge is shiftable along the longitudinal
axis to shift the flapper valve between a first position, wherein
the flapper valve is free to pivot relative to the valve seat, and
a second position, wherein the flapper valve is pivoted away from
the valve seat and maintained in an open configuration; and a
stationary sleeve arranged in the flowbore and fixed relative to
the inner surface.
2. (canceled)
3. The downhole tool according to claim 1, wherein the stationary
sleeve includes an inner surface portion including at least one
pocket.
4. The downhole tool according to claim 3, wherein the backpressure
valve cartridge includes an inner surface section and an outer
surface section and a hinge including a hinge pin that pivotally
supports the flapper valve.
5. The downhole tool according to claim 4, wherein the flapper
valve includes a hinge portion receptive of the hinge pin and a
valve portion including a sealing surface, the valve portion
extending radially outwardly of the hinge portion.
6. The downhole tool according to claim 5, wherein the flapper
valve includes a tang element that projects radially outwardly of
the hinge portion, the tang element being selectively received in
the pocket.
7. The downhole tool according to claim 1, wherein the backpressure
valve cartridge includes a ball seat.
8. The downhole tool according to claim 1, wherein the downhole
tool includes a locking mechanism that secures the backpressure
valve cartridge in the second position.
9. The downhole tool according to claim 8, wherein the locking
mechanism includes one or more collet fingers that are selectively
radially outwardly biased to secure the backpressure valve
cartridge in the second position.
10. The downhole tool according to claim 8, wherein the locking
mechanism includes a body lock ring.
11. The downhole tool according to claim 8, wherein the locking
mechanism includes a dog that is radially outwardly biased to
secure the backpressure valve cartridge in the second position.
12. A resource exploration and recovery system comprising: a first
system; a second system including at least one tubular extending
into a formation, the at least one tubular supporting a downhole
tool comprising: a tubular having an outer surface and an inner
surface defining a flowbore having a longitudinal axis; a
backpressure valve cartridge arranged in the flowbore, the
backpressure valve cartridge including a valve seat and a flapper
valve pivotally mounted relative to the valve seat, wherein the
backpressure valve cartridge is shiftable along the longitudinal
axis to shift the flapper valve between a first position, wherein
the flapper valve is free to pivot relative to the valve seat, and
a second position, wherein the flapper valve is pivoted away from
the valve seat and maintained in an open configuration; and a
stationary sleeve arranged in the flowbore and fixed relative to
the inner surface.
13. The resource exploration and recovery system according to claim
12, wherein the stationary sleeve includes an inner surface portion
including at least one pocket.
14. The resource exploration and recovery system according to claim
13, wherein the backpressure valve cartridge includes an inner
surface section and an outer surface section and a hinge including
a hinge pin that pivotally supports the flapper valve.
15. The resource exploration and recovery system according to claim
14, wherein the flapper valve includes a hinge portion receptive of
the hinge pin and a valve portion including a sealing surface, the
valve portion extending radially outwardly of the hinge portion,
the flapper valve further including a tang element that projects
radially outwardly of the hinge portion, the tang element being
selectively received in the pocket.
16. The resource exploration and recovery system according to claim
12, wherein the downhole tool includes a locking mechanism that
secures the backpressure valve cartridge in the second
position.
17. The resource exploration and recovery system according to claim
16, wherein the locking mechanism includes one or more collet
fingers that are selectively radially outwardly biased to secure
the backpressure valve cartridge in the second position.
18. The resource exploration and recovery system according to claim
16, wherein the locking mechanism includes a body lock ring.
19. The resource exploration and recovery system according to claim
16, wherein the locking mechanism includes a dog that is radially
outwardly biased to secure the backpressure valve cartridge in the
second position.
20. A method of operating a backpressure valve arranged in a
tubular having an inner surface defining a flowbore, the method
comprising: shifting a backpressure valve cartridge including a
valve seat and a flapper valve along a longitudinal axis of the
flowbore along a stationary sleeve fixedly connected to the inner
surface causing the flapper valve to transition from a first
position, wherein the flapper valve rests on the valve seat to a
second position, wherein the flapper valve is pivoted away from the
valve seat; and locking the flapper valve in the second position
with one or more collet fingers that snap into a recess formed in
the inner surface downhole of the flapper valve and the stationary
sleeve.
Description
BACKGROUND
[0001] In the drilling and completion industry boreholes are formed
to provide access to a resource bearing formation. Occasionally, it
is desirable to install a plug in the borehole in order to isolate
a portion of the resource bearing formation. When it is desired to
access the portion of the resource bearing formation to begin
production, a drill string is installed with a bottom hole assembly
including a bit or mill. The bit or mill is operated to cut through
the plug. After cutting through the plug, the drill string is
removed, and a production string is run downhole to begin
production. Withdrawing and running-in strings including drill
strings and production strings is a time consuming and costly
process. The industry would be open to systems that would reduce
costs and time associated with plug removal and resource
production.
SUMMARY
[0002] Disclosed is a downhole tool including a tubular having an
outer surface and an inner surface defining a flowbore having a
longitudinal axis, and a backpressure valve cartridge arranged in
the flowbore. The backpressure valve cartridge includes a valve
seat and a flapper valve pivotally mounted relative to the valve
seat. The backpressure valve cartridge is shiftable along the
longitudinal axis to shift the flapper valve between a first
position, wherein the flapper valve is free to pivot relative to
the valve seat, and a second position, wherein the flapper valve is
pivoted away from the valve seat and maintained in an open
configuration.
[0003] Also disclosed is a resource exploration and recovery system
including a first system, and a second system including at least
one tubular extending into a formation. The at least one tubular
supports a downhole tool including a tubular having an outer
surface and an inner surface defining a flowbore having a
longitudinal axis, and a backpressure valve cartridge arranged in
the flowbore. The backpressure valve cartridge includes a valve
seat and a flapper valve pivotally mounted relative to the valve
seat. The backpressure valve cartridge is shiftable along the
longitudinal axis to shift the flapper valve between a first
position, wherein the flapper valve is free to pivot relative to
the valve seat, and a second position, wherein the flapper valve is
pivoted away from the valve seat and maintained in an open
configuration.
[0004] Further disclosed is a method of operating a backpressure
valve including shifting a backpressure valve cartridge including a
valve seat and a flapper valve along a longitudinal axis of a
flowbore causing the flapper valve to transition from a first
position, wherein the flapper valve rests on the valve seat to a
second position, wherein the flapper valve is pivoted away from the
valve seat.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The following descriptions should not be considered limiting
in any way. With reference to the accompanying drawings, like
elements are numbered alike:
[0006] FIG. 1 depicts a resource exploration and recovery system
including a locking backpressure valve, in accordance with an
exemplary embodiment;
[0007] FIG. 2 depicts a cross-sectional side view of the locking
backpressure valve in a run-in configuration, in accordance with an
exemplary aspect;
[0008] FIG. 3 depicts a cross-sectional side view of the locking
backpressure valve in a production configuration, in accordance
with an exemplary aspect;
[0009] FIG. 4 depicts a cross-sectional side view of a locking
backpressure valve including a locking system positioned in a
locked configuration, in accordance with an exemplary aspect;
[0010] FIG. 5 depicts a cross-sectional side view of a locking
backpressure valve including a locking system positioned in an
un-locked configuration, in accordance with another exemplary
aspect;
[0011] FIG. 6 depicts a cross-sectional side view of the locking
backpressure valve of FIG. 5 showing the locking system positioned
in a locked configuration, in accordance with an exemplary
aspect;
[0012] FIG. 7 depicts a cross-sectional side view of a locking
backpressure valve including a locking system positioned in an
un-locked configuration, in accordance with still another exemplary
aspect; and
[0013] FIG. 8 depicts a cross-sectional side view of the locking
backpressure valve of FIG. 7 showing the locking system positioned
in a locked configuration, in accordance with an exemplary
aspect.
DETAILED DESCRIPTION
[0014] A detailed description of one or more embodiments of the
disclosed apparatus and method are presented herein by way of
exemplification and not limitation with reference to the
Figures.
[0015] A resource exploration and recovery system, in accordance
with an exemplary embodiment, is indicated generally at 2, in FIG.
1. Resource exploration and recovery system 2 should be understood
to include well drilling operations, resource extraction and
recovery, CO.sub.2 sequestration, and the like. Resource
exploration and recovery system 2 may include a first system 4
which takes the form of a surface system operatively connected to a
second system 6 which takes the form of a subsurface or
subterranean system. First system 4 may include pumps 8 that aid in
completion and/or extraction processes as well as fluid storage 10.
Fluid storage 10 may contain a gravel pack fluid or slurry, or
drilling mud (not shown) or other fluid which may be introduced
into second system 6.
[0016] Second system 6 may include a downhole string 20 formed from
one or more tubulars such as indicated at 21 that is extended into
a wellbore 24 formed in formation 26. Wellbore 24 includes an
annular wall 28 that may be defined by a wellbore casing 29
provided in wellbore 24. Of course, it is to be understood, that
annular wall 28 may also be defined by formation 26. In the
exemplary embodiment shown, subsurface system 6 may include a
downhole zonal isolation device 30 that may form a physical barrier
between one portion of wellbore 24 and another portion of wellbore
24. Downhole zonal isolation device 30 may take the form of a
bridge plug 34. Of course, it is to be understood that zonal
isolation device 30 may take on various forms including frac plugs
formed from composite materials and/or metal, sliding sleeves and
the like.
[0017] In further accordance with an exemplary embodiment, downhole
string 20 defines a drill string 40 including a plug removal and
production system 42. Plug removal and production system 42 is
arranged at a terminal end portion (not separately labeled) of
drill string 40. Plug removal and production system 42 includes a
bottom hole assembly (BHA) 46 having a plug removal member 50 which
may take the form of a bit or a mill 54. Of course, it is to be
understood that plug removal member 50 may take on various forms
such as a mill or a bit. BHA 46 may take on a variety of forms
known in the art.
[0018] Plug removal and production system 42 includes a selective
sand screen 60 arranged uphole of BHA 46. Selective sand screen 60
includes a screen element 62 that is arranged over a plurality of
openings (not shown) formed in drill string 40. It is to be
understood that the number of screen elements may vary. Further, it
is to be understood that screen opening size may vary. It is also
to be understood that screen element 62 may include a number of
screen layers. The openings in drill string 40 fluidically connect
wellbore 24 with a flow path 66 extending through drill string
40.
[0019] In yet still further accordance with an exemplary
embodiment, plug removal and production system 42 includes a
backpressure valve (BPV) 80 arranged downhole of selective sand
screen 60 and uphole of BHA 46. Referring to FIG. 2, BPV 80
includes a tubular 84 that forms part of drill string 40. Tubular
84 includes an outer surface 86 and an inner surface 88 that
defines a flowbore 90 having a longitudinal axis "L" that receives
BPV 80. Inner surface 88 includes a recessed section 92 that
supports a stationary sleeve 94. Tubular 84 is shown to include a
connector 97 that may be removed to provide access to flowbore
90.
[0020] In an embodiment, stationary sleeve 94 includes an inner
surface portion 99 and an outer surface portion 100. Outer surface
portion 100 includes one or move seal grooves (not separately
labeled) that receive seals, such as shown at 101, that engage
inner surface 88 of tubular 84. Stationary sleeve 94 includes a
first pocket 104a and a second pocket 104b that extend through
inner surface portion 99 to outer surface portion 100. Pockets 104a
and 104b facilitate operation of BPV 80 as will be detailed
herein.
[0021] In accordance with an exemplary aspect, BPV 80 includes a
backpressure cartridge (BPC) 110 including a first valve portion
112 including a first valve seat 114 and a first flapper valve 116
and a second valve portion 120 having a second valve seat 122 and a
second flapper valve 124. First valve portion 112 may be connected
to second valve portion 120 through a plurality of threads (not
separately labeled). A lock ring 128 may be employed to secure
valve seat 114 against first valve portion 112. Reference will now
follow to first valve portion 112 with an understanding that second
valve portion 120 includes similar structure.
[0022] First valve portion 112 includes an outer surface section
130 and an inner surface section 132, and an opening 134. Opening
134 is selectively receptive of first flapper valve 116. First
valve portion 112 includes a hinge 138 that receives a hinge pin
140 that pivotally supports first flapper valve 116. In further
accordance with an exemplary aspect, first flapper valve 116
includes a hinge portion 144 and a valve portion 146 having a
sealing surface 148. Hinge portion 144 is also shown to include a
tang element 154 that extends into pocket 104a. As will be detailed
herein, BPC 110 may be shifted along the longitudinal axis "L"
within flowbore 90 to shift first flapper valve 116 and second
flapper valve 124 between a first or closed position as shown in
FIG. 2 and a second position or open position as shown in FIG.
3.
[0023] In an embodiment, after mill 54 opens a downhole most plug
(not shown), BHA 46 may be pumped off and allowed to fall and
collect at a toe (not shown) of wellbore 24. During drilling, BPC
110 is arranged in the first position (FIG. 2) whereby first
flapper valve 16 and second flapper valve 124 are free to pivot in
first valve portion 112 and second valve portion 120 respectively.
In this manner, drilling fluids may pass downhole toward BHA 46 but
pressure may not pass uphole beyond BPV 80. That is, pressure
moving in an uphole direction would act against and cause first
flapper valve 116 and second flapper valve 124 to close.
[0024] After pumping off BHA 46, it may be desirable to produce
fluids through drill string 40. As such, BPV 80 is moved to the
second position (FIG. 3) opening flowbore 90. BPC 110 may be
shifted along the longitudinal axis "L" causing tang element 154 to
engage stationary sleeve 94 and shift first flapper valve 116 to
the open position. Second flapper valve 124 operates in a similar
manner. BPC 110 may be shifted through a variety of mechanisms
including shifting tools, fluid pressure (annular and/or tubular)
and drop balls. During production, it may be desirable to lock BPC
110 in the second position to ensure that flowbore 90 remains
open.
[0025] In an exemplary aspect shown in FIG. 4, wherein like
reference numbers represent corresponding parts in the respective
views, BPC 110 includes a locking mechanism 164 that is connected
to second valve portion 120. Locking mechanism 164 includes an
object seat, such as a ball seat 166 that may be receptive of an
object such as a drop ball 167 employed to facilitate shifting BPC
110 to the second position and a body lock ring 168. Body lock ring
168 includes first and second ring members (not separately labeled)
each having corresponding tooth elements (also not separately
labeled). The tooth elements may be angled to allow axial moving in
one direction while resisting axial movement in an opposite
direction. Thus, after shifting to the second position, locking
mechanism 164 maintains first and second flapper valves 116 and 124
in the open configuration. At this point, while described as a drop
ball, it should be understood that the object may take on various
forms including balls, darts, plugs and the like.
[0026] Reference will now follow to FIGS. 5 and 6, wherein like
reference numbers represent corresponding parts in the respective
views, in describing a locking mechanism 173 in accordance with an
exemplary aspect. Locking mechanism 173 is connected to second
valve portion 120 and may include a ball seat 175 that receives a
drop ball 176. Locking mechanism 173 may also include one or more
collet fingers such as shown at 177 that shift along with BPC 110
from the first position (FIG. 5) to the second position (FIG. 6) in
which collet fingers 177 snap into a recess 180 formed in inner
surface 88 thereby locking first flapper valve 116 and second
flapper valve 124 in the open configuration.
[0027] Reference will now follow to FIGS. 7 and 8, wherein like
reference numbers represent corresponding parts in the respective
views, in describing a locking mechanism 190 in accordance with an
exemplary aspect. Locking mechanism 190 is connected to second
valve portion 120 and may include an object seat, such as a ball
seat 192 that receives a drop ball 193. Locking mechanism 190 may
also include an annular recess 194 that is receptive of a radially
expandable dog 196. BPC 110 may be shifted from the first position
(FIG. 7) by pressuring up against drop ball 193 to the second
position (FIG. 8) in dog 196 expands radially outwardly into a
groove 199 formed in inner surface 88 thereby locking first flapper
valve 116 and second flapper valve 124 in the open
configuration.
[0028] At this point it should be understood that the exemplary
embodiments describe a system for actuating a backpressure valve by
shifting a self-contained backpressure valve cartridge. The
backpressure valve cartridge includes a valve portion having a
valve seat and a flapper valve. The flapper valve may be shifted
from one position to another position simply by moving the
backpressure valve cartridge. A locking mechanism may be employed
to lock the flapper valve in position after shifting. It should be
understood that while shown as including two valve portions,
backpressure valve cartridge may include any number of valves.
Further, while shown as being shifted to open valves, it should be
understood that the cartridge could also be shifted to close
valves.
[0029] Set forth below are some embodiments of the foregoing
disclosure:
[0030] Embodiment 1. A downhole tool comprising: a tubular having
an outer surface and an inner surface defining a flowbore having a
longitudinal axis; and a backpressure valve cartridge arranged in
the flowbore, the backpressure valve cartridge including a valve
seat and a flapper valve pivotally mounted relative to the valve
seat, wherein the backpressure valve cartridge is shiftable along
the longitudinal axis to shift the flapper valve between a first
position, wherein the flapper valve is free to pivot relative to
the valve seat, and a second position, wherein the flapper valve is
pivoted away from the valve seat and maintained in an open
configuration.
[0031] Embodiment 2. The downhole tool according to any prior
embodiment, further comprising: a stationary sleeve arranged in the
flowbore and fixed relative to the inner surface.
[0032] Embodiment 3. The downhole tool according to any prior
embodiment, wherein the stationary sleeve includes an inner surface
portion including at least one pocket.
[0033] Embodiment 4. The downhole tool according to any prior
embodiment, wherein the backpressure valve cartridge includes an
inner surface section and an outer surface section and a hinge
including a hinge pin that pivotally supports the flapper
valve.
[0034] Embodiment 5. The downhole tool according to any prior
embodiment, wherein the flapper valve includes a hinge portion
receptive of the hinge pin and a valve portion including a sealing
surface, the valve portion extending radially outwardly of the
hinge portion.
[0035] Embodiment 6. The downhole tool according to any prior
embodiment, wherein the flapper valve includes a tang element that
projects radially outwardly of the hinge portion, the tang element
being selectively received in the pocket.
[0036] Embodiment 7. The downhole tool according to any prior
embodiment, wherein the backpressure valve cartridge includes a
ball seat.
[0037] Embodiment 8. The downhole tool any prior embodiment,
wherein the downhole tool includes a locking mechanism that secures
the backpressure valve cartridge in the second position.
[0038] Embodiment 9. The downhole tool any prior embodiment,
wherein the locking mechanism includes one or more collet fingers
that are selectively radially outwardly biased to secure the
backpressure valve cartridge in the second position.
[0039] Embodiment 10. The downhole tool any prior embodiment,
wherein the locking mechanism includes a body lock ring.
[0040] Embodiment 11. The downhole tool any prior embodiment,
wherein the locking mechanism includes a dog that is radially
outwardly biased to secure the backpressure valve cartridge in the
second position.
[0041] Embodiment 12. A resource exploration and recovery system
comprising: a first system; a second system including at least one
tubular extending into a formation, the at least one tubular
supporting a downhole tool comprising: a tubular having an outer
surface and an inner surface defining a flowbore having a
longitudinal axis; and a backpressure valve cartridge arranged in
the flowbore, the backpressure valve cartridge including a valve
seat and a flapper valve pivotally mounted relative to the valve
seat, wherein the backpressure valve cartridge is shiftable along
the longitudinal axis to shift the flapper valve between a first
position, wherein the flapper valve is free to pivot relative to
the valve seat, and a second position, wherein the flapper valve is
pivoted away from the valve seat and maintained in an open
configuration.
[0042] Embodiment 13. The resource exploration and recovery system
any prior embodiment, further comprising: a stationary sleeve
arranged in the flowbore and fixed relative to the inner surface,
wherein the stationary sleeve includes an inner surface portion
including at least one pocket.
[0043] Embodiment 14. The resource exploration and recovery system
any prior embodiment, wherein the backpressure valve cartridge
includes an inner surface section and an outer surface section and
a hinge including a hinge pin that pivotally supports the flapper
valve.
[0044] Embodiment 15. The resource exploration and recovery system
according to any prior embodiment, wherein the flapper valve
includes a hinge portion receptive of the hinge pin and a valve
portion including a sealing surface, the valve portion extending
radially outwardly of the hinge portion, the flapper valve further
including a tang element that projects radially outwardly of the
hinge portion, the tang element being selectively received in the
pocket.
[0045] Embodiment 16. The resource exploration and recovery system
according to any prior embodiment, wherein the downhole tool
includes a locking mechanism that secures the backpressure valve
cartridge in the second position.
[0046] Embodiment 17. The resource exploration and recovery system
according to any prior embodiment, wherein the locking mechanism
includes one or more collet fingers that are selectively radially
outwardly biased to secure the backpressure valve cartridge in the
second position.
[0047] Embodiment 18. The resource exploration and recovery system
according to any prior embodiment, wherein the locking mechanism
includes a body lock ring.
[0048] Embodiment 19. The resource exploration and recovery system
according to any prior embodiment, wherein the locking mechanism
includes a dog that is radially outwardly biased to secure the
backpressure valve cartridge in the second position.
[0049] Embodiment 20. A method of operating a backpressure valve
comprising: shifting a backpressure valve cartridge including a
valve seat and a flapper valve along a longitudinal axis of a
flowbore causing the flapper valve to transition from a first
position, wherein the flapper valve rests on the valve seat to a
second position, wherein the flapper valve is pivoted away from the
valve seat.
[0050] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the invention (especially in
the context of the following claims) are to be construed to cover
both the singular and the plural, unless otherwise indicated herein
or clearly contradicted by context. Further, it should be noted
that the terms "first," "second," and the like herein do not denote
any order, quantity, or importance, but rather are used to
distinguish one element from another.
[0051] The terms "about" and "substantially" are intended to
include the degree of error associated with measurement of the
particular quantity based upon the equipment available at the time
of filing the application. For example, "about" and/or
"substantially" can include a range of .+-.8% or 5%, or 2% of a
given value.
[0052] The teachings of the present disclosure may be used in a
variety of well operations. These operations may involve using one
or more treatment agents to treat a formation, the fluids resident
in a formation, a wellbore, and/or equipment in the wellbore, such
as production tubing. The treatment agents may be in the form of
liquids, gases, solids, semi-solids, and mixtures thereof.
Illustrative treatment agents include, but are not limited to,
fracturing fluids, acids, steam, water, brine, anti-corrosion
agents, cement, permeability modifiers, drilling muds, emulsifiers,
demulsifiers, tracers, flow improvers etc. Illustrative well
operations include, but are not limited to, hydraulic fracturing,
stimulation, tracer injection, cleaning, acidizing, steam
injection, water flooding, cementing, etc.
[0053] While the invention has been described with reference to an
exemplary embodiment or embodiments, it will be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted for elements thereof without departing from the
scope of the invention. In addition, many modifications may be made
to adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the claims. Also, in
the drawings and the description, there have been disclosed
exemplary embodiments of the invention and, although specific terms
may have been employed, they are unless otherwise stated used in a
generic and descriptive sense only and not for purposes of
limitation, the scope of the invention therefore not being so
limited.
* * * * *